Carbon cycling in the world's deepest blue hole
"Blue holes are unique geomorphological features with steep biogeochemical gradients and distinctive microbial communities. Carbon cycling in blue holes, however, remains poorly understood. Here we describe potential mechanisms of dissolved carbon cycling in the world's deepest blue hole, the Yongle Blue Hole (YBH), which was recently discovered in the South China Sea. In the YBH, we found some of the lowest concentrations (e.g., 22 μM) and oldest ages (e.g., 6,810 years BP) of dissolved organic carbon, as well as the highest concentrations (e.g., 3,090 μM) and the oldest ages (e.g., 8270 years BP) of dissolved inorganic carbon observed in oceanic waters. [...]"
Source: JGR Biogeosciences
Authors: P. Yao et al.
Hydrochemical properties and chemocline of the Sansha Yongle Blue Hole in the South China Sea
"Blue holes can provide valuable information regarding paleoclimate, climate change, karst processes, marine ecology, and carbonate geochemistry. The Sansha Yongle Blue Hole, located on Yongle Atoll in the Paracel Islands in the South China Sea, is the deepest blue hole in the world. A comprehensive investigation of the blue hole was conducted to determine the hydrochemical properties and associated redox processes active in the water column. Results indicate the presence of two thermoclines, one at 13–20 m and a second at 70–150 m, dividing the water column into five stratified water layers. [...]"
Source: Science of the Total Environment
Authors: Linping Xie et al.